PT-141, also known as bremelanotide, is a synthetic peptide that works similarly to the natural hormone melanocortin. It is FDA-approved to treat hypoactive sexual desire disorder (low sex drive) in premenopausal women. It is also used to treat low libido and erectile dysfunction in men.

The beneficial effect of PT-141 on sexual activity in men and women was discovered by accident. Initially, the drug was explored as a way to increase skin pigmentation. Its ability to increase sexual desire was an unexpected side effect.

PT-141 is available as a subcutaneous injection and as a nasal spray. Clinical trials have shown that peptides pass from the nasal cavity to the brain.

Hypoactive sexual desire disorder affects 8.9% of women between the ages of 18 and 44, 12.3% of women between the ages of 45 to 64, and 7.4% of women over the age of 65. Low sexual desire tends to increase with age, but distress associated with the disorder decreases, which means that the condition’s prevalence is consistent across ages. Low sexual desire is linked with lower health-related quality of life, lower overall happiness, and a higher risk of anxiety and depression.

Female sexual dysfunction is a constellation of symptoms, including decreased desire, interest, arousal, orgasm, or pain with sex. Two large clinical trials demonstrated PT-141 safety and efficacy. Women using bremelanotide had a statistically significant improved sexual desire. Unlike previous treatment options, bremelanotide (PT-141) does not interact with alcohol.

PT-141 appears to act on melanocortin receptors 3 and 4 in the brain. It enhances sexual arousal and penile erections by releasing dopamine, a neurotransmitter in the brain.

In a double-blind placebo-controlled study, approximately 80% of men developed an erection satisfactory for intercourse after using PT-141 whether the cause of ED was physical or psychological, and 68% of men reported an increase in sexual desire.

Clinical trials are underway to further investigate PT-141; early results show that PT-141 is effective for men with diabetes and ED and for men who do not respond well to oral ED medications.

PT-141 (bremelanotide) is a nonselective agonist of the melanocortin receptors type 3 and 4, which means that it binds to these receptors and induces a similar effect to when natural peptides bind to these receptors. It is the active metabolite of Melanotan II.

In the brain, PT-141 influences sexual behavior by stimulating dopamine release from the medial preoptic area in the brain, an area of the brain associated with sexual behavior.

PT-141 acts in the brain, where it can induce penile erections and increase libido. Traditional oral ED meds act on blood vessels.

Traditional oral ED medications increase nitric oxide levels in blood vessels, increasing blood flow into the penis. The neurons in the parasympathetic nervous system trigger the release of nitric oxide from the inner lining of blood vessels, causing the blood vessels to dilate and the smooth muscle lining the corpora cavernosa in the penis to relax. Blood flows into the corpora cavernosa, increasing pressure within the penis and causing an erection.

Nitric oxide causes a cascade of chemical reactions to increase blood flow into the penis. The enzyme phosphodiesterase class 5 (PDE5) inhibits these reactions. Oral ED medications block PDE5.

PT-141 should not be taken in conjunction with other ED meds as it may increase the risk of priapism, a prolonged erection that can damage the penis if untreated.